Apparatus for electroplating articles having pockets or recesses therein



Dec. 9, 1947. J, V, LUNDSTRQM I 2,432,322

A?PARATUS FOR ELECTROPLATING ARTICLES HAVING POCKETS OR RECESSES THEREIiI Filed Feb. 9, 1944 M V .F up

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I I, 1 m '1 Dal/j]? m V a v Inventor:

k John V. Lundst'rom y Jud-M His Atto ney.

Patented Dec. 9, 1947 UNITED STATE APPARATUS FOR ELECTROPLATING AR- TICLES HAVING POCKETS OR RECESSES THEREIN John V. Lundstrom, Scotia, N. Y., assignor to General Electric Company, a corporation of New York Application February 9, 1944, Serial No. 521,620

The present invention is an electroplating apparatus, particularly for chromium plating articles having one or more pockets or recesses therein. Ordinarily in electroplating articles such as reamers, drills, taps, dies and other articles having pockets where gas may collect, the electro deposited metal either does not plate in the recesses or the plating is uneven and incomplete leaving exposed bare portions of the foundation or base metal, This is due to the fact that if an article is hung in an electroplating bath the lower portion of the article tends to receive the heaviest metal coating because the hydrogen gas given off during the plating process forms a curtain in front of the article to be plated and this ourtain increases progressively in thickness from the bottom to the top of the article to be plated. In electroplating an article having pockets or recesses therein the hydrogen gas trapped in such pockets resists deposition of any metal therein.

It is an object of the present invention to provide an apparatus suitable for electroplating metallic devices having pockets or recesses therein. It is a further object of the invention to provide an apparatus for chromium plating tools such as reamers,-drills, taps, dies and the like. Other objects will appear hereinafter.

The novel features which are characteristic of my invention are set forth with particularity in the appended claim. My invention itself however will best be understood from reference to the following specification when considered in connection with the accompanying drawing in which Fig. 1 is a view partly in elevation and partly in section of an apparatus whereby my invention may be carried into effect; while Fig. 2 is a detail view on an enlarged scale of a portion of the apparatus disclosed in Fig. 1.

Referring more particularly to the drawing, I have indicated at I a metal tank containing a plating solution or electrolyte 2 which may be for example a chrome plating bath as set forth in the patent to Fink No. 1,581,188, the tank having a suitable electrical connection such as binding post 3| and conductor 32 connected to any suitable direct current source of energy not shown. An electrically conducting bar 3 extends across the top of the tank and is insulated therefrom by channeled insulators 4 and 5. The bar 3 is connected to the same source of direct current as conductor 32. The article to be plate is illustrated as a reamer 6 rigidly mounted in a holder 1'. The holder l is detachably secured to one end of a metal bracket 8, the other end of the bracket being provided with a cup-shaped mem- 1 Claim. (01. 204-199) 1 2 i o, her 9 which bearsagainst a spring ill. The spring 5!] forces a plate H into contact with oneend of an-insulated electrically conducting rod I2. The opposite end of conductor i2 is connected to one of two inverted V-shaped members i3 and M secured to the underside of a wooden or other suitable platform I5. The platform l5 rests on the rod 3 and edge of the tank l. The V-shaped members I3 and Hi are supported on the bar or rod 3. The intermediate portion of the bracket 8 is secured to a rotatable cylindrical member It by meansof screws IT. The member [6 is made of insulating material and is rotatably mounted on the insulated conducting rod l2. A bevel gear I8 is bolted to the member l6 and engages a second bevel gear l9 mounted on a vertical shaft 20 which is driven through gears 21 and 22 by an electric motor 23. The shaft20 and motor 23 are supported on a base 24 which is mounted on platform I5.

A cylindrical insulator 25 provides a bearing for the insulated conducting rod 12 and is in turn supported on a bearing in a flat bar 26 of any suitable insulating material, for example a composition having a phenol-aldehyde resin base. The bar 25 is rigidly secured to the base 24 in any suitable manner. A bearing 21 for shaft 20 is rigidly secured to the bar 26 by means of a bolt 28. -A coiled spring 29 is secured at one end to the bar 26. The other end of the spring engages the vertical portion of the insulated conducting rod l2 and forces the opposite end of the conductor l2 into contact with the plate ll.

Although the tank I may serve as the anode, I prefer to employ one or more lead plate anodes, not shown, which may be mounted in the tank I and connected to the other terminal of a direct current source of power. A handle which comprises two vertical portions 3i] and a horizontal portion, not shown, permits removal from the tank I of the entire electroplating apparatus with the exception of the conducting bar 3. In order to prevent undesired plating of any metal portions of the electroplating apparatus such portions may be covered with a lacquer or other suitable insulation.

In operation, electric current flows from the anode through the electrolyte to the cathode article 6 to be plated and through the bracket 8, spring I0, and the conducting rod l2. In the meantime motor 23 rotates the insulating member l6 and the article to be plated. The axis of the article to be plated is considerably offset from the axis of rotation of the member It so that the article to be plated describes a cylindrical to the diameter of the article to be plated. This Wide circle of rotation shakes off any trapped hydrogen which may have collected in the pockets in the reamer 6 and apparently prevents hydrogen from collecting at the reamer'S. Asa result the electrodeposited coating is applied evenly-over the entire article including any pockets or recesses therein where gas might ordinarily collect.

Although I have illustrated myinvention .particularly in connection with chromium plating, it will be understood that it is not restricted to chromium plating but may be employed in electroplating zinc, cadmium or other metals where gases are evolved in the plating ope-ration.

What I claim as new and desire to secure by Letters Patent of the United States is:

An electroplating apparatus comprising a tank for holding an electrolytic bath, a disk of insulat ing material mounted therein for rotation about a horizontal axis, a metal bracket secured to said disk and flexibly connected to a stationary, in-

sulated, conducting rod \extending through said disk, said-stationary rod being connected to one pole of asource of electric current, said bracket being provided with a socket for detachably and rigidly/supporting the article to be plated at one end thereof for rotation about the axis of said disk during the plating operation, and means for completing an electric circuit through the -said tank, electrolytic bath, article and bracket. JOHN V. LUNDSTROM.

REFERENCES CITED The following references are of record in the file of this patent:

5 UNITED STATES PATENTS Number Name Date 615,940 Wright Dec. 13, 1898 986,823 Heaphy Mar. 14, 1911 m 1,036,571 Corey Aug. 27, 1912 1,154,604 Bois'sier Sept. 28, 1915 733,404 :Fahrenwald Oct. 29, 1929 1,747,165 Eaton Feb. 18, 1930 1,861,272 Hilddrf et a1 May 31, 1932 T5 1,950,096 Yeager Mar. 6, 1934 1,956,625 Ritter May 1, 1934 2,351,321 .Compton June 13, 1944 2,382,233 Kiv'ley et a1 Aug. 14, 1945 FOREIGN PATENTS 20 Number Country Date 304,029 Great Britain Jan. 17, 1929 323,947 Great Britain Jan. 16, 1930 412,685 Great Britain July 5, 1934 25 OTHER REFERENCES Journal of the Electrodepositors Technical So- :ciety, vol. 13 (1937), Paper No. 7, pages 3 and Figs. 4 and 5 of said :paper. 

